[pydanticgen] Add slot URIs in pydantic (v2) module output for semantic (web) applications.

[markdoerr]

Is your feature request related to a problem? Please describe.
For semantic - aware python applications, it would be very useful to be able to use the slot_uri information of a LinkML YAML data model, best through the generated Pydantic module output. How could this be achieved ?

Describe the solution you'd like
The generated output should contain the slot_uris in the generated Pydantic Model.

How important is this feature? Select from the options below:
• Important - it's a blocker and can't do work without it

When will use cases depending on this become relevant? Select from the options below:
• Short-term - 2-4 weeks

Additional context
Implementation wise, it is quite flexible, there should only be a clear relation between the slot_uri and a generated pydantic field.

[markdoerr]

This issue should be solved with #b5313f9 .